Blog # 4 Describe the three types of selection: directional, stabilizing and disruptive and give an example of each in your own words

directional selection
when individuals at one end of the curve have higher fitness than individuals in the middle or at the other end,directional selection takes place.such as,if there is a snack with normal venom,another snack has overwhelming venom.but the habitat they live are full with some strong prey who need to be kill by the powerful venom.then,the snack with overwhelming venom will be survive.as the result,the average venom intensity will be increase.

stabilizing selection
when individuals near the center of the curve havee higher fitness than individuals at either end of the curve,stabilizing selection takes place.for example,if there are two extremely lizards,one isyellow,and the other is purple.however,the nomarl lizards should be green.the yellow lizard's struggle is its color will make it die easier in its environment,and the purple one' color causes it can not hide itself perfectly.therefore,the amout of yellow and purple will decrese while the green one will have more offfspring.

disruptive selection
when individuals at the upper and the lower ends of the cureve have higher fitness than individuals near the middle,disruptive selection takes place.here it is,if there are three kind of horse,the first is small,the second is normal,and the third one is big.when they face a lion at the same time,the small one can run away very fast,the big one can threat the lion and make it afraid to attack,while the normal can do nothing.because of that,the population of the small and big one will raise,but the normal size will be decline.

Blog #3 Explain what microevolution is? What are the three ways that variation occurs?

microevolution is a change in gene frequency within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift.Population genetics is the branch of biology that provides the mathematical structure for the study of the process of microevolution. Ecological genetics concerns itself with observing microevolution in the wild. Typically, observable instances of evolution are examples of microevolution; for example, bacterial strains that have antibiotic resistance.

These are the three ways that variation can occur.
1.mutation
A mutation is any change in a sequence of DNA.Mutations can occur because of mistakes in the replication of DNA or as a result of radition or chemicals in the environment,
2.gene shuffling
it occurs during the production of gametes
3.crossing-over
occurs during meiosis.Further increases the number of different genotypes that can appera in offspring.

Blog # 2 Why is fossil record hard to interpret?

First of all,fossil is a very ancient substance.lt occurs long time ago,can you regonzine a thing after millons of years?As a result,it is very hard to interpret fossil record because it's very old.Also,after evolution,many animals and plants alter their shape and apperance a lot.lt is more hard to distinguish them.People can just infer or guess which thing does this fossil record represent.The result may be unclear.Fossil is a staff with mysterious.lt kind of werid,too.The experiment on them will depend a lot of environment,history,and biology' knowledge.All in all,the fossil record is really hard for people to interpret or demonstrate.

Blog #1

Why is evolution a theory and not a law?
l think the most important reason for evolution is a theory because it can not be prove vividly or precisely by our telenogy now.lt  may be wrong or not totally correct,so it suppose not be a law.lt is just a good and beliveable demonstration.lt will be replace by more advanced and nicely theory in the future.Also,the earth occurs in this universe for a long time.lt's very hard to observe it clearly.Evolution theory can't be one hundred percent right.ln short,it's not a law because it depends some scientists' guess,and don't have enough essential details to show it is true without any doubt.

last blog of the semester

What was you favorite activity/topic this year? Why was it a favorite?
My favourite activity of this year ids the strawberry lab occured about one week ago.l think it's interesting and funny.The first  reason is l like to eat strawberry.l also feel to see the DNA is a very amazing and awesome thing,l see a small thin materal with pink and a little black.Thats's the DNA which l first see.However,it's a  impressive lab.

What was your least favorite? Why?
My least favourite is the kimi chip.l forget how to spell it.l don't like because l forget to bring it,or it will be funny,too.Hopefully,l can taste it next time.l really like fendentmal food.lt's health and delicious

If you could change one thing (Not the amount of homework) what would it be and how would you change it?
lf l could change one thing,l will change my study's attitude more good and with more intersting and be more careful.l use my effort in next semster and be better.

Blog#13 How has DNA changed how we investigate crimes?

l think DNA is a very helpful and important invention,especially make the police and decteive to find out the crimal easily.lf there is a careless robber left their blood in the crime scene.Then,it's possible to have a investigation on that blood.We can find the unique DNA from it.Consequently,we can find the truely robber easily a lot than before.Also,even if the murder left a small hair,we can also find out who's DNA is it.Like in the movie,Vincent's one litttle hair has all of the DNA,and it's a very important clue in that movie.However,the invention of DNA help a lot in the crimes.We don't really need a lot of wisdom people like Selock Homes.We can easily find out who is the final murder depend on one modern evidence:DNA!

Why does P1 look all alike and F1 looks very different?

p1 look all like because their allen are always all the same,and its offspring will be identical as its parent.When Mendel let two differert plants doing sex,their children F1 will choose the dominant allen between their parent,and they will always become that.For example,if a tall plant is sex with another short plant,and the tall allen is dominant.For this reaason,their children will all become tall.The short allen are recessive,but it will be affect their grandchildren.